Because the matching itself happens after the event, people do not feel pressured to select or reject each other in person.
A 2005 study at the University of Pennsylvania of multiple Hurry Date speed dating events found that most people made their choices within the first three seconds of meeting.
Furthermore, issues such as religion, previous marriages, and smoking habits were found to play much less of a role than expected.
A 2006 study in Edinburgh, Scotland showed that 45% of the women participants in a speed-dating event and 22% of the men had come to a decision within the first 30 seconds.
Most speed dating events match people at random, and participants will meet different "types" that they might not normally talk to in a club.
On the other hand, the random matching precludes the various cues, such as eye contact, that people use in bars to preselect each other before chatting them up.